This invention relates to commercial dishwashing machines, and more particularly to a dishwashing machine including an integrated recycling system for recycling water through the dishwashing machine.
Commercial dishwashing machines include a wash chamber having spray units located therein which are adapted for spraying wash water and rinse water onto racks of dishes that are positioned within the wash chamber. The dishwashing machines may be single station type units in which dishes to be washed is maintained in the wash chamber during the wash and rinse cycles, or multi-station units in which the dishes are moved through the unit on a conveyor apparatus. Conventionally, commercial dishwashing machines include upper and lower wash spray units and upper and lower rinse spray units to ensure that the rack of dishes is sprayed from above and below during the wash and rinse cycles. Typically, at least the wash water that is supplied to the upper and lower wash spray units is recirculated through the dishwashing machine by a recycling system which includes a pump that draws wash water from a sump and supplies the wash water to the upper and lower spray units. The wash water is returned to the sump through a suitable filter to be recirculated.
The two primary ways of recycling wash water in a dishwashing machine are by utilizing an external pump system or an internal pump system. In an external pump system, the pump motor and the impeller are contained within a pump housing forming a pump assembly that is mounted externally to the sump. The inlet of the pump assembly is connected through a filter to an output of the sump, allowing the pump assembly to draw wash water from the sump and pump the wash water to the upper and lower wash spray units of the dishwashing machine. In an internal pump system, the pump motor is located externally of the sump, but the impeller and the pump housing are mounted within the sump of the dishwashing machine. When the impeller is rotated by the pump motor, wash water from the sump is drawn into the pump housing and pumped to the upper and lower wash spray units of the dishwashing machine.
A significant shortcoming of external and internal pump systems is the need to cast or fabricate a complex pump housing adapted to mounted either inside or outside the housing of the dishwashing machine. Such a requirement may add as much as $100.00 to the fabrication costs of the pump assembly.